JPH0763212A - Nut locking device - Google Patents

Abstract

PURPOSE:To utilize a space outside a nut by forming a groove in a circumferential direction of a male screw, which groove is agreed with a leading end tapered portion of a locking screw which fixes the nut to the male screw, locating a head side end of the locking screw inner than an outer peripheral surface of the nut, and providing a locking means for the locking screw. CONSTITUTION:A locking screw 25 provided on a nut 24 is a headless hexagon socket heat cap screw, and is screwed into a locking screw hole 37 penetrating the nut 24 in a diameter direction. The locking screw 25 has a leading end formed to be a truncated conical tapered portion 38, and has such a length that a head is not projected from an outer peripheral surface of the nut 24 when screwed to the extent of abutting against a side surface 40 of a groove 39 of a male screw 3. The groove 39 has a V-shaped section, and the side surface 40 which is agreed with a leading angle of the tapered portion 38 of the locking screw. The groove is formed on the way of the male screw 34 corresponding to the position of the leading end of the locking screw in a circumferential direction. A portion around an opening of the locking screw hole 37 is plastically deformed in respect to a nut 22 and the locking screw 25 which are sufficiently screwed as a locking means 26 for the locking screw 25. Margin space outside the nut is enlarged, which can be utilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a locking device for a nut, which is effective when applied to a rod nut of a cylinder, for example.

[0002]

2. Description of the Related Art As a conventional technique of this kind, a full-fledged Japanese Utility Model Publication No. 52-
There is one described in No. 21372. As shown in FIG. 5, this nut loosening prevention device is provided with a piston 2 in a cylinder 1.
Is applied to the nut 5 for fixing the piston rod 3 to the piston rod 3, and the nut 5 screwed onto the male screw 4 of the piston rod 3
Is provided with a set screw 9 having an inclined surface 9a at its tip, and the male screw 4 is provided with an annular groove 10 having an inclined surface 10a. The inclined surface 9a of the set screw 9 is attached to the inclined surface of the annular groove 10. It is designed to be closely attached to 10a. With such a configuration, the nut 5 is prevented from being loosened by the axial force F generated by the tightening force of the set screw 9.
A lock nut 11 is screwed onto the set screw 9.

[0003]

The head side of the set screw 9 for preventing the loosening of the nut 5 projects from the outer peripheral surface of the nut 5 for screwing the lock nut 11, and the head of the set screw 9 is formed. The side is close to the inner peripheral surface of the cylinder 1. In recent years, the hydraulic pressure used to reduce the size of hydraulic cylinders has been increased. For example, the inner diameter of the cylinder can be reduced by increasing the pressure of the hydraulic oil while keeping the output of the cylinder constant. In such a case, there is a problem that the head side of the set screw 9 projects from the outer periphery of the nut 5 and approaches the inner peripheral surface of the cylinder 1. That is, in general, the size of the piston rod is determined by the buckling strength, the screw strength for fixing the piston to the piston rod, and the like, so that the piston rod cannot be thinned when the pressure is increased. Therefore, when the pressure is increased, the cylinder inner diameter tends to approach the outer diameter of the piston rod, the screw diameter of the piston mounting portion, and the outer diameter of the piston fixing nut. Then, there is a problem that the inner diameter of the cylinder cannot be reduced due to that.

Further, in general, in order to prevent the nut from loosening which requires a reliable loosening prevention, when the above-mentioned conventional anti-loosening device using a lock nut as a set screw is applied, a portion protruding from the outer periphery of the nut is applied. Due to the existence of the problem, it is difficult to provide a member to be provided close to the outer circumference of the nut, and it is easy for something to get caught when the nut is exposed,
There is a problem that the appearance is not good. The present invention aims to solve the above problems.

[0005]

Means for Solving the Problems According to the means of the present invention, in a nut loosening prevention device for fixing a nut to a male screw with a set screw, the tip of the set screw is formed into a conical or truncated cone taper portion. Together, a groove having a side surface having an angle substantially matching the tip angle of the taper portion is provided in the male screw portion along the circumferential direction, and the head side end of the set screw is located inside the outer peripheral surface of the nut, It is characterized in that a means for preventing the set screw from loosening is provided. The groove is preferably provided in the middle of the male screw so that the male screw portions on both sides of the groove are screwed into the nut. It is preferable that the loosening prevention means plastically deforms the peripheral portion so as to reduce the inner diameter of the set screw hole formed in the nut. Separately, the loosening prevention means fixes the friction member to one side so as to increase the frictional resistance in the rotational direction between the set screw hole provided in the nut and the set screw screwed into the set screw hole, and the other is fixed to the other. It is better to provide the pressure contact with the. Separately, it is preferable that the loosening prevention means mechanically engages the set screw with a set screw hole provided in the nut. The nut may be a rod nut of a cylinder.

[0006]

Since the tip of the set screw is formed into a conical or frustoconical taper portion, and the groove having the side surface having an angle substantially equal to the tip angle of the taper portion is provided in the male screw portion along the circumferential direction. , By fully screwing the set screw, an axial acting force in the direction opposite to the loosening direction of the nut is obtained, and the head side end of the set screw is located inside the outer peripheral surface of the nut. Since there is no protrusion, and the locking screw is provided with locking means, the nut is reliably locked.

[0007]

EXAMPLE A first example is shown in FIGS. As shown in FIG. 2, this embodiment is a loosening prevention device for the nut 24 when the piston 22 of the hydraulic cylinder 21 is fixed to the piston rod 23 by the rod nut 24, and uses a set screw 25. is there. In the figure, 30 is a head cover, and 31 is an inner peripheral surface of the cylinder. As shown in Figure 1,
The piston 21 is formed in a ring shape, and the female screw portion 32 formed in the inner hole of the piston 21 is screwed into the male screw portion 33 formed in the piston rod 23. In the nut 24, a female screw 35 formed in the inner hole of the nut 24 is screwed into a male screw 34 formed in the piston rod, and is in contact with the end surface of the piston 22.

The set screw 25 provided on the nut 24 is shown in FIG.
As shown in an enlarged view in FIG. 3B, a nut 24 is screwed into a set screw hole 37 penetrating in the radial direction with a headless hexagon socket head cap screw. The end of the set screw 25 is formed in a tapered portion 38 having a truncated cone shape, and the head side does not protrude from the outer peripheral surface of the nut 24 when screwed until it comes into contact with the side surface 40 of the groove 39 described below. It is about the length. The groove 39 has a substantially V-shaped cross section and has a set screw 2
A side surface 40 is formed to match the tip angle of the tapered portion 38 of No. 5, and is an annular shape provided along the circumferential direction in the middle of the male screw portion 34 corresponding to the tip position of the set screw 25. When the set screw 25 is screwed in sufficiently and the tapered portion 38 is brought into contact with the side surface 40, the set screw 25 receives a reaction force and the nut 24
Is pressed against the end surface of the piston 22 with which the nut is in contact. As the loosening preventing means 26 for the set screw 25, the nut 22 in a sufficiently screwed state
With respect to the set screw 25, a punch having a conical tip at two places, for example, at two peripheral portions of the set screw 25 on the outer peripheral surface of the nut 22, that is, the peripheral portion where the set screw hole 37 is opened, has small recesses 41. It is hit to such an extent that it is formed and plastically deformed. As a result, the set screw 25 cannot be easily rotated, and the set screw 25, which functions to prevent the nut 24 from loosening, is prevented from loosening.

A second embodiment is shown in FIG. 4 (a). This embodiment is different from the first embodiment only in the loosening prevention means for the set screw 25, and therefore other parts are omitted and only the main parts are shown, and the same parts are shown by the same reference numerals. Is omitted. The loosening prevention means is such that a small hole 43 in the radial direction is bored in the middle of the set screw 25 and a nylon plug 42 is installed to reach the crest of the set screw 25. When the setscrew 25 is screwed into the setscrew hole, the nylon plug 42 is deformed and screwed into the threaded portion of the setscrew hole and comes into pressure contact, so that the rotational friction of the setscrew 25 increases. This is strongly rotated to bring the tapered portion 38 into contact with the side surface 40. As a result, the set screw 25 prevents the nut 24 from loosening without easily rotating.

In the third embodiment, although not shown, an adhesive is applied when the set screw 25 is screwed into the set screw hole. The set screw 24 that prevents the nut 24 from loosening is fixed by the solidification of the adhesive.

A fourth embodiment is shown in FIG. 4 (b). This embodiment is different from the first embodiment only in the loosening prevention means for the set screw 25, and therefore other parts are omitted and only the main parts are shown, and the same parts are shown by the same reference numerals. Is omitted. The loosening prevention means is provided with a C-shaped stop ring 44 on the head side of the set screw 25. This prevents the set screw 25 from coming off, and the set screw 24 that prevents the nut 24 from loosening is held at that position.

In each of the first to fourth embodiments, the set screw 25 is provided with the loosening preventing means in a state in which the head side thereof does not protrude from the outer periphery of the nut 24, so that the loosening preventing action of the nut 24 is maintained. In addition, it is not necessary to provide a large extra space on the outside of the nut. For this reason,
The inner diameter of the cylinder can be made smaller than before. Therefore, it is effective for downsizing the hydraulic cylinder. Further, in some cases, it is possible to make a part of the hydraulic device provided in the cylinder head or the cylinder head part accommodating the hydraulic device project into the spare space, which is also effective for size reduction.

Although the above-mentioned embodiments are all applied to the nut for mounting the piston of the cylinder, they can generally be applied to the nut for which reliable loosening prevention is desired, and in that case, a margin space can be secured outside the nut. At the same time, there are advantages such as a good appearance, and things are not caught.

[0014]

According to the invention described in claim 1, since the head of the set screw does not project to the outer periphery of the nut, when the outer member is located outside the nut, the nut and the outer member are more likely than the conventional one. This has the effect of increasing the margin space between the nuts, allowing the use of the margin space, and preventing the loosening action of the nut from deteriorating as compared with the prior art.

According to the second aspect of the invention, the groove is provided in the middle of the male screw, and the male screw portions on both sides of the groove are screwed into the nut. If the lengths are the same, the screwing length becomes longer than in the conventional case, and the strength of the threaded portion is increased. Claim 3
According to the invention described above, the loosening prevention means plastically deforms the peripheral portion so as to reduce the inner diameter of the set screw hole provided in the nut, thereby making it difficult for the set screw to come off.
The effect that it is not necessary to use another part is produced. According to the invention as set forth in claim 4, the loosening preventing means includes one of the friction members so as to increase the frictional resistance in the rotational direction between the set screw hole provided in the nut and the set screw screwed into the set screw hole. It is fixed so that it is pressed against the other, the surface pressure of the sliding surface rises, the friction resistance increases, and the set screw does not come off easily.Assembling is completed simply by screwing the set screw. Has the effect of doing. According to the invention of claim 6, since the nut is a rod nut of a cylinder, there is an effect that it is effective for downsizing of the hydraulic cylinder by the amount that the extra space outside the nut can be used.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a main part of a first embodiment of the present invention.

FIG. 2 is a partial vertical cross-sectional view showing the outline of the cylinder of the embodiment.

3A and 3B show details of the embodiment, FIG. 3A is an enlarged plan view of a set screw portion of FIG. 1, and FIG. 3B is a sectional view taken along line AA of FIG.

FIG. 4A is an enlarged sectional view of a set screw portion of the second embodiment, and FIG. 4B is an enlarged sectional view of a set screw portion of the fourth embodiment.

FIG. 5 is a vertical cross-sectional view of a conventional nut loosening prevention device.

[Explanation of symbols]

 21 Cylinder 22 Piston 23 Piston Rod 24 Rod Nut 25 Set Screw 26 Locking Means 34 Male Thread 35 Female Thread of Nut 36 Female Thread of Set Screw 37 Set Screw Hole 38 Tapered Part 39 Groove 40 Groove Side 41 Recess 42 Nylon Plug 43 Small Hole 44 Retaining ring

Claims (6)

[Claims] 1. A nut locking device for fixing a nut to a male screw with a set screw, wherein a tip portion of the set screw is formed into a conical or frustoconical taper portion, and a tip angle of the taper portion is substantially equal to that of the taper portion. A groove having side faces with matching angles is provided in the male screw portion along the circumferential direction, the head side end of the set screw is located inside the outer peripheral surface of the nut, and a loosening prevention means for the set screw is provided. A nut loosening prevention device characterized in that 2. The nut locking device according to claim 1, wherein the groove is provided in the middle of the male screw, and the male screw portions on both sides of the groove are screwed into the nut. 3. The nut slack preventer according to claim 1, wherein the slack preventer plastically deforms a peripheral portion of the nut so as to reduce an inner diameter of a set screw hole provided in the nut. apparatus. 4. The slack preventing means fixes a friction member to one side so as to increase frictional resistance in a rotational direction between a set screw hole formed in the nut and the set screw screwed into the set screw hole. The nut locking device according to claim 1 or 2, wherein the nut locking device is provided so as to come into pressure contact with the other. 5. The nut anti-loosening device according to claim 1 or 2, wherein the anti-loosening means mechanically locks the set screw in a set screw hole provided in the nut. 6. The nut locking device according to claim 1, claim 2, claim 3, claim 4, or claim 5, wherein the nut is a rod nut of a cylinder.